0TreeLemur

PC system is not an autopilot. It was not designed to hold a heading. So even with the PC system you must maintain heading. That said, if it is working properly, you can take your hands off for 10 seconds at a time and expect no upsets, even in light/mod. turbulence. Being driven by the TC, it rapidly detects roll and counteracts it. You must maintain heading with frequent, minor corrections unless it is perfectly calm. However, add the Accutrak and the PC system will follow a magenta line perfectly, even in 72 kt crosswinds. All you need to do is manage the trim to maintain elevation. Apollo-era technology still going strong. Also +1 for reactivating an existing related thread. Shows you are doing your research! Good on ya!

What's a monney?

Some folks repair them if not too bad. Some use MEK mixed with pieces of PET. I used plastic epoxy reinforced with fiberglass to close up and strengthen corner fatigue cracks.

Dehumidification is the key. Local dew point reduction inside the hangar, and cooling the air inside the hangar so that it is "cool enough" but not cooler than the outside air dew point. Get the R.H. in your hangar down below 40%, at an air temperature no less than say 80F for those steamy summer months. Do that and you'll have done the best you can do. Fans will keep it feeling comfortable when you are in there. Man, I wish I could do this but I'm in a big uninsulated common hangar with 11 other a/c. Insulation will greatly reduce the sensible heat load on your system. Dehumidification normally creates sensible heat, adding to the amount of heat that you must pump out of your hangar. So, designing such a system is, well, complicated. If you cool the air temperature in your hangar below the outside air dew point, you are asking for trouble in two ways. First, your hangar will be come a dew machine, especially where not or poorly insulated and anyplace where air leaks in (e.g. door). Second, your aircraft will become a dew machine when you take it out to fly. Takeoff quickly and now you've got moist air flow inside your cool aircraft and condensation everywhere- on the tubular steel frame, inside the wings, throughout the fuselage.

That is a great question, and I can't exactly answer it, but it happened. Four yellow EGT bars about the time I lifted off the ground. Very unusual. WAG- Maybe with full power, at low speed, and cowl flaps closed it got an extra 200F hotter below the engine, which added to the temperature read by the EGT probes? As I wrote, the engine was warm. I had landed, filled up with fuel and taken off again when this happened.

While this thread considers JPI EDM limits, I have a related question. Recently we upgraded to the Hartzell Top Prop on our C. It has no rpm limitations when installed on an O-360. Anybody ever send their JPI back in to get limits changed? I still get the red numbers in the old "no-continuous ops" rpm range. I'd rather not see them since they no longer apply. Not a big deal, but if I had time to ship it back to JPI I might.

I forgot to open the cowl flaps on our C one day, on t/o with a warm engine, and boy it caused the EDM900 to scream. EGT color bars went into the yellow fast- like right after wheels up. Three seconds of WTF???, a check of full rich mixture, and I noticed closed cowl flaps. Opened them and lowered the nose to 120 kias and things cooled off pretty fast. They make a large difference. On t/o with a warm engine, I often must keep speed on climb out to about 110-120 to keep CHT 4 below 410F, with cowl flaps full open. Haven't tested with partially open cowl flaps.

This is an excellent data point for those who inquire about buying aircraft that have been sitting for a few years.

Nobody buys an airplane to save money. We buy them to save time. Going by the equation: time=money Maybe we do save money. But boy, does it cost a lot!

I would really like to add altitude hold to my a/c. Was it working when removed? PM sent. I want it if its working!

Not looking to buy right now. Trying to learn from others and plan for the future. I read this older thread:

Our M20C has a Brittain Accutrak II, and it works great. Love it. Follows the magenta line like a bloodhound! I've been waiting for Brittain to get back on its reconstituted feet, and get the remaining parts I need for altitude hold. I'm in contact with Cecilia Henderson once or twice per year. Brittain coming back to life just doesn't seem to be happening. I own a controller with the trim eye indicator that is yellow tagged. I a checkout for the altitude hold chamber part, which I own. I need to acquire the elevator servos. I see used autopilot systems for sale here and there. Knowing nothing about them except that some companies don't like to issue STC's for used equipment... Hypothetically, is there a make/model used A/P for sale out there that (1) includes the M20C on the AML, (2) is not a total disaster to install, (3) I can get permission from the manufacturer to install? Since I ask hypothetically it doesn't mean that I have money burning a hole in my pocket. I'm not gonna drop $20k+ installing a new A/P in a C, don't even mention it. I'm not gonna go glass, I likes my 6-pack. It's a C. I'm keeping her a while, and would really love to have altitude hold- that's all. TT-BK is soooooooo sloooooooooooow, and because it says BK means $$ once it happens. What about Trio? I think waiting for a new STC for a C is a loooong wait. The market is too small and uneconomical. Used seems to be the way to go. Anyone been there/done that? Suggestions? Thanks! -Fred

I'm guessing you don't have a J-bar? In that system gear down microswitch is accessible and tickleable. Another nice feature of that system.

Yeah- not much of an update. Maybe they edited a misspelled word. I liked it because the focus on older aircraft and some ballpark pricing. Helps me keep my expectations in check.

Interesting article. Notably absent is the word "Mooney" https://www.planeandpilotmag.com/article/install-new-autopilot-used-plane/

And where water pours out of the aft overhead air vents if the drain tube is blocked. Or- if you fly through the remnants of a tropical storm and overwhelm the drain tube .

Yes, now that you mention the name, Bill Shuert was the person who advised me to de-activate the AoA in my AV-20-S.

I hear you and I agree that certified avionics should not be open source. I want the vendors skin fully in the game. The AV-20-S is NORSEE. If they open sourced the code we could fix their bug. They would still have to approve it and compile. I suppose they would have to flash the ROM too. The one I purchased has no USB port.

I wonder the same thing. I was in contact with Aerovonics before uAvionics bought them with a request for a software update. The response from Aerovonics was to not expect the AOA to work on a Mooney. That doesn't really bother me because I bought it for the timer, TAS, and mems AI functions. There is obviously a bug in the TAS calculation code, because it doesn't calculate it correctly I've e-mailed uAvionics three times. First time I got a "I'll pass your request to engineering..." with no reply. The next two e-mails both received no replies. Wish they would reply to legitimate customer questions - they should. At our Mach numbers the constant of proportionality between IAS and TAS with a few decent assumptions is sqrt(ρ/ρo), the square root of air density ratio, with ρ=Ps/RT. The device measures Ps & T, and R is approximately constant within less than 2% for air. Yet, the AV20s gives erroneously high TAS indications, at least in my case, which I find supremely annoying. IAS to TAS conversion is easy as the little vernier scale on some AS indicators shows. Perhaps someone forgot to take the sqrt() of the air density ratio when they wrote the firmware. I'd help debug it if they would share. Wouldn't an open source programmable NORSEE device like the AV-20-S be cool?

A cell phone provides backup GPS. If paired with an iPad you get moving maps. I also carry a $90 "Dual" brand WAAS GPS in my flight bag as another backup. All that stuff will work even if ships' electrics go T.U.

The Lamar Technologies STS-A12-PMA sold by Spruce is equivalent, and considerably lower cost. I recently bought one that I don't need. I'd sell it to you for the same amount I paid Spruce for it if you are interested.

Here it is. Courtesy of the MS Time Machine... 6041H231-1.pdf

@MikeOH you are correct. Here's a great example of the alternative to the transistor in avionics:

I agree- it is amazing the technology we have today compared to what was in our birds. And that 21.2 lb DME could probably toast bread!

There is a valley of dearth in the Mooney price distribution between about 65-90k, except maybe the occasional problem J. Assuming this bird with an overtime engine is worth $52k, with a zero time engine that would put it squarely in the middle of where there are none. Maybe its changed recently and I haven't been watching prices lately. I'm skeptical, but maybe I'm wrong. Have C prices been going up considerably?